What I understand is you want to create functionality which can export dashboard as powerpoint-presentation file.
You need to write the whole python library to generate dashboard into power-point file. But you can get external python libraries' help to read the dashboard, to generate power-point file, etc.
Same thing is done for Splunk's export PDF functionality in Splunk. This steps requires a lot of efforts for sure, but currently no solution available out there.
Manually if you want to do it, you either take screenshots and add to powerpoint or you can export PDF and try to convert into power-point.
Do you also mean you want to download the XML of a dashboard, or the HTML output as rendered when you view it? One will require file system access, the other will require the use of something like requests or beautifulsoup.