There are two modes to the color modulator. Solid mode and LFO mode. In solid mode the entire shape is a single color - and the way to modulate the color change rate is with the "hue rot" dial that is under the "saturation" dial.
In LFO mode, the color modulation is performed in HLS color space - and each component (hue, lightness, saturation) has its own modulation controls. To modulate the speed of the hue you would adjust the "hue mod" dial (the one to the right of "hue width".
In general the "width" dials of each control determines how wide the values are applied around where the color chooser UI node is, and the mod dial controls how fast the modulation occurs.
Hope that makes sense.