There are two ways to import a diagram into Google Drive:

  1. Create a new diagram in Google Drive and import the file using File, Import or drag and drop the file into the new diagram (hold down the alt key to keep the original cell locations).
  2. Add an .xml extension to the filename, upload it to Google Drive and open it in using File, Open. If a revision is created (Ctrl+S) or the file is saved, the .xml extension is no longer needed.