How to open Google Drive links directly in Google Drive app Is there a way to do this?
Currently, the GDrive links I click in my emails open in Safari.

Is this currently a limitation of the app (or iOS 7)? Is there a configuration I can change?
Apparently you can prepend the url with the respective Google app to which it belongs. So if it is a Google Sheet, prepend the url with Googlesheets://. If it is a doc, I'm guessing you would use Googledocs://
So if the url is http://docs.google.com/spreadsheets/Google-document/, amend it with the appropriate app prefix (in this case Googlesheets:// like so: Googlesheets://http://docs.google.com/spreadsheets/Google-document.
PS: The issue is discussed at length here.