Williams was making his first regional start since October
Blues: (36) 48
Tries: Powell, R Williams (3), Phillips, Blair (2), Macleod
Cons: Blair (3), Macleod
Edinburgh: (0) 0
Cardiff Blues ripped apart a makeshift Edinburgh side at the Arms Park to keep alive their slim league title hopes.
Wales back Rhys Williams proved the star of the show, back from serious injury with a first-half hat-trick.
Andy Powell, Mike Phillips and Ben Blair also got tries before the break for a half-time lead of 36-0.
The home side then relented somewhat, but Blair got his second and Nick Macleod completed the rout, the Scots failing to trouble the scorers.
The opening quarter was quiet, the visitors - missing eight backs to injury, including captain Chris Paterson - struggling to put their game together.
The Blues' aggressive forwards gradually began to make a mark, and skipper Xavier Rush's bullocking run from midfield proved the spark for the first try.
Backs and forwards carried strongly, hooker Rhys Thomas making the biggest dent, before recycled ball came back to Powell.
I just had to run the scores in and I have to thank the boys for setting me up
The back-rower, making his first regional start of the season after shoulder reconstruction, had momentum in his run and ran through full-back Alistair Warnock from 10 yards out.
Then it was the turn of another injury returnee, Williams, to profit.
Blair set up the 44-cap Wales international's first try with a delightful step inside, giving Williams - in his first Blues game since tearing the muscle off his thigh bone in October - a simple run-in.
With confidence increasing the Blues set off on an attack from their own 22, Powell breaking the line and carrying to halfway where he found Phillips, the scrum-half finishing from 50 yards.
The bonus point was secured in the 33rd minute, Phillips taking a quick tap penalty before sending Williams in for his second score.
There's no excuse, coming here and not playing is not good enough
Edinburgh coach Lynn Howells
Two minutes later outside-half Macleod's break provided Williams, who has targeted a place on Wales' summer tour to Australia, with a memorable first-half hat-trick.
To cap Edinburgh's miserable first half, Blair again ripped their defence apart with a length-of-the-field try to make it 36-0 at the break.
The Cardiff side mercifully eased off after half-time, but on 64 minutes they attacked from their own line.
The ball came to Ed Fairhurst on halfway who chipped over the threadbare defence, allowing Blair to gather and cross for his second score.
With Edinburgh replacement lock Fergus Pringle in the sin-bin, Macleod rounded off the scoring two minutes from time.
Another chip over the top found the cover defence absent, allowing the outside-half to regather for an easy score.
Man-of-the-match Rhys Williams:
"I was just so glad to be back on the field - I had the winter off and now I'm looking forward to the summer.
"It was easy for me on the wing, I just had to run the scores in and I have to thank the boys for setting me up.
"That performance was important for the team, we knew we had to be more clinical than last week in Connacht."
Edinburgh coach Lynn Howells:
"It was poor, we lacked the physicality of the game, had no structure, and paid the price.
"There's no excuse. The Blues played very well, but coming here and not playing is not good enough."
Blues: Blair, R. Williams, Shanklin, Stcherbina, Czekaj, Macleod, Phillips, Jenkins, Thomas, G. Powell, Davies, Sidoli, A. Powell, M. Williams, Rush.
Replacements: N. Robinson for Blair (67), Luveitasau for Czekaj (52), Fairhurst for Phillips (52), G. Williams for Thomas (70), Filise for G. Powell (64), Jones for Sidoli (61), Lewis for Rush (67).
Edinburgh: Warnock, Lopez Fleming, Jorgensen, Dey, Cairns, Godman, Laidlaw, Jacobsen, Kelly, G. Cross, Bentley, Murray, Hogg, MacDonald, Callam.
Replacements: Hodge for Jorgensen (49), Senio for Laidlaw (72), Hall for Kelly (61), Dickinson for G. Cross (40), Pringle for Bentley (40), Strokosch for MacDonald (72), Taylor for Callam (51).
Referee: George Clancy (Ireland)