Yes, you make it the same way as you create any other textures, just get you template and
take it to your favorite paint program and apply your colors to the template.

For making MT5s just go to the Material Room, select the article you want to make
an MT5 of and press the + sign at the bottom of the library list.
It will give you a pop-up window called New Material Set.
Put a name in the Set Name box and then select Single Material and press OK.
And now you have an MT5.

If you want to, you can also do a Material Collection, which is an MC6.
Just press Material Collection instead of Single Material in the pop
up window and then press Select Materials. 
In the next pop-up window check all the parts you
want in your MT5 and uncheck the parts you don't want to be in it.
Hit OK.  Then hit OK again for the New Material  Set  window.
And now you have a Material Collection, an MC6.
This is useful if your clothing item has more than one set
of colors or patterns on the various parts of the cloths, such
as if you have a belt or buttons and you want them to be
a different color than the dress itself.