Hayden scored on a 5-yard run with 8:46 left in the third quarter and Cole Hedlund's extra point gave the Razorbacks (1-0) a 35-0 lead. Williams' second touchdown, a 1-yard run on the first play of the fourth quarter, made it 42-0.
The Arkansas defense limited Florida A&M (1-1) to 175 yards of total offense, including 49 in the first half.
Cornerback Henre' Toliver returned a fumble 18 yards for a touchdown on the first possession of the second half as Arkansas began to blow the game open after leading 21-0 at halftime.
Florida A&M, an FCS school, scored its only touchdown on a 7-yard pass from Vincent Jefferies to Brandon Norwood with 8:23 remaining in the fourth quarter. The score capped a 15-play, 76-yard drive that was kept alive when freshman punter Chris Faddoul scooped up a bounced snap and ran 26 yards for a first down.
The Razorbacks had 415 yards of total offense, including 236 yards rushing. Sophomore Devwah Whaley, Arkansas' first-team tailback, gained 60 yards on 12 carries, including a 5-yard run for the game's first touchdown with 1:18 left in the first quarter.
Arkansas senior quarterback Austin Allen completed 14 of 19 passes for 135 yards. Allen was intercepted once and threw a 16-yard touchdown pass to Deon Stewart in the second quarter.
Arkansas' backup quarterback, redshirt freshman Cole Kelley, threw a 7-yard pass to tight end Cheyenne O'Grady with 2:20 left in the fourth quarter for the game's final touchdown.