There are 4 predefined skins:
The desired one is set through the enumeration DHXScheduler.Skins:
Scheduler.Skin = DHXScheduler.Skins.Terrace; // applies the 'terrace' skin to the scheduler
Note, if none of predefined skins fits you, you can design your own one using online DHMTLX Skin Builder. See details here.
Thank you for your feedback!