In the existing connectivity graphs, the Granger results do not use the colormap as the other measures. The color represent the directionnality of the measure: from the low color (in the colorbar) to the high color, or green for bidirectional connections.
In the spectrum or image views, if you click on a value, you'll see its label with the format "A x B", it means the value from A to B.
Note that we are in the process of updating these graph figures and they will soon change a lot.