The 5th and last input argument is a list of the colors for each data point. If you have N data points, then the colors is an N by 3 list of RGB values in the range 0-1. You can set their color based on certain other attributes. For example if you want them all red except for where the "value" array is more than 1000, you can do
myColors = [ones(N,1), zeros(N,1), zeros(N, 1)]; % Initialize all red.
for k = 1 : N
if value(k) > 1000
myColors(k, :) = [0,0,1]; % This row will be blue.
end
end
It could be vectorized if you want.