Hair colors are not adjusted by a parameter dial. Instead, you have to apply a MAT pose. 
In the Pose library you'll find a folder Goddess Hair MAT. Inside, you'll see several icons of hair colors.
Select the hair figure, double click the icon with the color you want, and you're done.

You may not see the color in the document window. In that case, choose the menu Display -> Document Style -> Texture shaded.
Next, select the hair figure (doesn't matter what part of the hair) and choose Display -> Figure Style -> Use Document Style.
If that doesn't help, click on a visible part of the hair and choose Display -> Element Style -> Use Figure Style.
Now the hair should show up in its full glory.

The pen is mightier than the sword. But if you literally want to have some impact, use a typewriter

My gallery   My freestuff