Unfortunately, it is not possible to change the graphs in the policy compliance reports or dashboards. The images used are fixed but I will forward a feature request to allow users to have more options for different presentation graphics.
Some customers do use the API to feed the configuration and reporting data to other systems (Such as MSSQL Reporting Services or IT GRC solutions) when custom manipulation or the report formating is required. The advantage of using the API is you can automate the report generation view the integration of Qualys and another reporting platform.
Additionally, I have seen other PC customers use Excel macros on the CSV formatted exported reports as well.
I will forward your request to Product Management for review but want to let you know that the current images are not configurable.
You may not be aware that you can also copy the data that makes the charts to memory (clipboard), so you may be able to paste the data into a macro as well. This is a manual process but might be useful if you are trying to explain a topic in the report.
For example, open a policy report in the HTML view.
Right click on a graphic and choose, copy data to clip board
You can paste the information into another application for custom reporting, here is the example of the text pasted to notepad
The trend graphs have the numeric data available as well
Provides this data
As mentioned, this is a manual process but may be useful if a nuance of the 3D graphics needs to be explained.