You can create truly unique layouts for the 404 Pages using the Divi Theme Builder. The layout designed and applied to the 404 Page will replace the default 404 Page layout with a Divi layout.
Go to WordPress Dashboard → Divi → Theme Builder
Click on the Add New Template icon
Choose the Build New Template option
In the modal window, scroll to the bottom and check the 404 Page option
Click on the Create Template button
Click on the Add Custom Body label
Build the layout that is going to be used for the 404 Page
Note: You can also load and use any of Divi's premade layouts as a starting point.