As the other posters said, he simply must not go backwards in a straight line. He should work on angles, and circling away.
Stay off the fence. He needs to keep the fight in the middle of the octagon, and he absolutely needs to control the distance. If Cain rushes to close that range, circle out while jabbing and reset in the middle.
That's where he's most effective with his boxing-style strikes.
Be very active with the jab; don't let Cain get confortable, and make him pay for rushing in.
It also appeared to me that Cain was doing too much damage while on top for JDS to implement any sort of offensive BJJ, and I suspect that wouldn't change in any potential future rematch.
So forget the BJJ; train footwork, distance, a nice long/busy jab, and keep working on that defensive wrestling.
I'd like to see 'em go at it again.