As far as I know there is no requirement that says you have to keep your payoth 'looking good.' But if that is priority to you then there are two different options.
If one has naturally curly hair that allows peyoth to develop naturally when drying, then on yom tov one may simply wet his hair in the morning when he gets up.
For everything else, one should wrap his peyoth around his finger, then put all the windings to the side of his head, and pin the windings to the side of his head with a bobby pin or hair pin before going to bed. And then in the next morning simply unpin your peyoth and they should fall back down into their original curly shape.