Apple - Is there a way to export syntax color settings from one Xcode installation to a new one?
Custom syntax color themes are located in
~/Library/Developer/Xcode/UserData/FontAndColorThemes/
(Note that this directory may not exist if you've not yet modified any of your themes or haven't created a custom theme of your own, but will be created as soon as you do.)
The files have a .dvtcolortheme
extension. Simply retrieve the file from that directory and copy it into the same directory on another machine.
I quite like Ethan Schoonover's Solarized themes; I find them to be very readable and easy on the eyes, and can be installed as explained above.