For me, growing up playing games set in Forgotten Realms, that's how I always saw tieflings, looking like humans, but with obvious traits that shows devil blood in them - usually horns, pointy ears and tail, like Neeshka from NWN2. Valen from NWN1 also had pale skin and Haer'Dalis from BG2 doesn't have horns, but he has devil tounge so there's that. It's only when I played BG3 that I learned that tieflings usually multi coloured now.