Here's another pic of an SK with a bit of a more 'punk' look.I do understand. I remember being surprised that this guy was a shadar-kai at first. Still, it is a take I kind of like, especially since fluff wize they are all about extreme sensations to keep from fading.
One possibility is that the pale SKs are Shadowborn SK's, eg those born in the Shadowfell. The 'punk' guys might be from a splinter group born on the material plane. Although, it's not clear how the SK's are different from humans, other than being INCREDIBLY angst-ridden and born in the Shadowfell. So an SK from our world might just be a human with a weird haircut.