Reminds me of Clarke's Childhood's End, where the good guys have to wait decades before revealing their physical appearance, because they happen to look like the bad guys from a certain religion.
It wasn't happenstance, though. There is a specific reason as to why humanity's depictions of demons look the same as those aliens, and it's a critical plot point. (Can't say more or I'll spoil one of the best sci-fi books of all time for those who haven't read it).
Edit: it's also highly debatable whether the Overlords are in fact the good guys.
Don’t want to spoil it either, so only can reply that literature and movies are good at masking the real horrors of the world that most of the world has to live in. Can’t remember how well society was in the book though.
Edit: it's also highly debatable whether the Overlords are in fact the good guys.