I agree with Bjorn that it's possible to get caught up in this, and it is going to take some work to make something nicer looking than
But here is a way to at least mess around in less time. With the colorwheel function below you can display a color wheel and then use the datatips feature on the plot to pick some rgb point near the edge. Then convert rgb to hue, saturation and value. For a point on the edge, every color has saturation = 1 and hue is what ever you like. For simplicity I used value (i.e. brightness) = 1 all the time and did not vary it.
The code below uses constant hue and varies the saturation (from .1 to 1 in this example) to make the color map. Obviously you can pick two points on the color wheel in lots of different ways and interpolate between those to make the color map.
map = hsv2rgb([h(1)*ones(n,1) linspace(satmin,1,n)' ones(n,1)])
huu = angle(-x+i*y)/(2*pi) + 1/2;
val = val*ones(size(huu));
hsv = [huu(:) sat(:) val(:)];
rgb = reshape(rgb,2*n+1,2*n+1,3);