Zat Knight's own goal had put Grayson's men ahead, only for Mark Davies and Chris Eagles to turn the game in Bolton's favour.
But Vaughan, on his return from a thigh injury, earned the Terriers a point three minutes from time to the delight of his manager.
Grayson said: "We are delighted to have him back in the team. We have seen previously what he can do for us and the quality he has."
He continued: "If you paid money to come and watch this game I don't think you were short changed.
"The game swung backwards and forwards and I have kicked every ball and gone through every emotion. We made some mistakes but we could have nicked it at the end."
Grayson also singled out Alex Smithies, who saved a Chris Eagles penalty midway through the second-half, after his blunder had gifted a goal to Leeds last weekend.
His manager said: "Alex is a fantastic goalkeeper and he made a mistake last week but he showed his quality.
"He's mentally strong and goalkeepers need that. They can be heroes one minute and villains the next."