Maybe it's because Cale is often describe as someone who hates to move around and often hurts himself even though he never meant to lol
And about his long hair, along with his journey here and there it is sometime mentioned that Cale's hair starts to grow long and if you look at the cover of the novel he also has long hair
Yeah he's sometimes described as beautiful. He also got long hair if you look at the novel cover you can see how he looks later on.
Cale resembles his mother a lot. He was often described as a handsome, frail-looking young master. And he even lost weight over time. He purposefully acted weak most of the time too. Maybe that's why the fanarts are really feminine.
Is Cale in the novel described to have a bit feminine features? Because in every fanart of him he is drawn as a delicate guy with long hair