You can do it if you install the NI Vision Development Module.
NI Vision Development Module (VDM) is designed to help you develop machine vision applications and support lots of Vision Utilities including color conversion.
After installing VDM, you can find IMAQ RGBToColor 2 VI
in Function pallet.
The path is Vision and Motion»Vision Utilities»Color Utilities»IMAQ RGBToColor 2 VI.
IMAQ RGBToColor 2 VI converts an RGB color value into another format. Therefore, you can control many types of color format like RGB, HSL, HSV and so on.