We gave interior designers Darren Jett, Noz Nozawa, and Xavier Donnelly a photo of the same empty bedroom for a young professional—and then asked each of them to renovate it in their particular style.

Turquoise is a happy beachy color. It is the color of the ocean, sometimes, and there’s different shades of it here along with some other pretty blues. That glass lamp on the turquoise bed table is ...