How to maintain pivot chart format after refresh?
Solution 1:
Select the data series in your pivot chart. Right click and select Format Data Series... Select the color option (paint bucket), and select solid fill (or whatever you want), but the key is to select something other than automatic. Set the colors you want. Save the file, exit (not sure exiting is necessary, but you can find out for yourself), open the file, refresh your pivot table(s) and your formatting should remain as you last set it.