Hi there, you can paint and I'm not sure if it's got buttons, but if it does those can be changed too. If you're feeling adventurous you can also recover the ottoman. Here's a tutorial that will help you do that - https://www.youtube.com/watch?v=onNjOIb5U4U
Make a slip cover with some denim or similar fabric using a glue gun.
Make a cover for it w/ elastic or pull ties on bottom.