Just go into extra tweaks at the bottom, under all the ui tweaks. There is an option to reset to default.
Thanks.
A couple updates:
First, I tried exporting the UI colors to XML per one of the options but it just keeps telling me there's an error writing the file.
Second, it'd be nice if each color selector started out at the current color so that you could make note of it. It'd be even better if each item had a Reset to Default just for that item.
Third, in the default view I can't even see 3G and there seems to be no control to change its color. However, I've also been keenly aware that since moving to v10 my 3G has been nearly always absent entirely. Could just be coincidently but I am keeping an eye on it.
I also just used the option above recommended by Kratos and it didn't reset my colors back to default. Hmm.