Right after your post - @wheaten replied where to download it.
1.Download the file:
GitHub - All version Peppymeter screen
2.Unpack on your computer
3. Transfer the entire unpacked folder (peppy_screensaver) via FTP to:
/home/volumio
4.Connect via SSH to volumio:
cd /home/volumio/peppy_screensaver
volumio plugin install
Reboot