Gritty Social's Divi Switch plugin (one of the plugins included in the Ultimate Divi Bundle) comes with a range of useful Divi customizations. One is the ability to add a pre-loader effect to the homepage, which displays a spinning icon while your page loads.

If you'd like to modify Divi Switch's pre-loaders to work on all pages, you can do so by adding CSS to Divi as follows:

Now when you use Divi Switch to switch on either the "Home Page Pre-Loader (Dark)", or "Home Page Pre-Loader (Light)", it'll be applied to all pages on your site.