I attempted to render point clouds with the VFX Graph in an HDRP scene. This project is based on Keijiro's Pcx. Therefore, you can generate colour and position maps from imported ply files, which will be used for your VFX graphs.
The original point cloud was created by ediacara
If you don't have any point cloud (ply) file, one of the easiest ways to get it is to visit Sktechfab and find a downloadable point cloud. Then just drag and drop it into your Unity project. Once it's imported, click on the icon and have a look at the inspector window. By default, it is Mesh, so change it to Texture and hit Apply. Now, expand it and you will see its colour and position textures inside.
This repository has been updated in accordance with the workshop I gave to Interactive Media Arts students at NYU Shanghai in October and then I have left some unnecessary files as well in order to have exactly the same project as before. A recording is available here.