specifying colors in gplotmatrix

i am ploting some data with gplotmatrix, and i have more than seven categories which i want to plot in different colors. gplot allows to specify color of markers with short names of colors like r for red, g for green. But when i have numerious categories, i run out with short names of colors(known codes rmgbyckw). So if i want to specify a particular color e.g. siena, what i have to do? .

gplotmatrix( class_info(4,:)', class_info([1 2 3],:)',class_info(5,:)'...
    ,'rmgbyc','o*oxsdpxs',[],'on',[5,5,5,5,5,5,5,5],...
    categories(4,:),categories([1,2,3],:));

Answer 1

[Sukuchha]

bump

Answer 2

[Sukuchha]

bump again. Somebody ?