Yes you can!
This feature is particularly useful if you have spent time customising the settings as you like, and you'd like future videos to have the same design settings.
When you've finalised all settings and are ready to publish your video, click on FINISH in the top right corner. You will then see this screen:
Check the "Save as Theme?' checkbox. You'll then have to enter a name for the theme.
Click on DONE after entering the theme name.
You can find this theme inside your Editor. This theme will be available to you in the 'Themes' tab.