Demons look like that in Medieval and Renaissance paintings. "Red dude with horns" didn't become the standard depiction of demons until much later.

In modern representations, I think you'd be hard-pressed to find red-dude-with-horns. Seems like we shifted towards hot-dude-with-something-off (Lucifer series, Good Omens), when we do see red-dude-with-horns I feel like it's meant to be somewhat ironic/on-the-nose (south park, preacher).