Here is some GTL code to produce a Waterfall Plot for % Change in Tumor Size from baseline at Visit 2 coloured by group using SAS 9.2.
The figure below does not seem so advance at first howerver, there are a lot of things going on. Firstly the x-axis is ordered by decreasing % change from baseline. Secondly, the subjects are coloured by another variable (Group), and thirdly the percentage changes are shown on top of or below the bar charts. Enjoy!