NOTE: Although as of the writing of this article currently Github Enterprise cloud (hosted on Github.com) is not currently fully supported, it is possible to set up an Integration with Snyk and have it work using the following steps!
Generally, you want to follow the steps in the Github Integration page
Select Github Enterprise from the Integrations menu to begin configuring the integration. When asked to input the URL of your Github Enterprise Server, it's important that you input https://api.github.com and not any other variation of the URL.
As mentioned above, this is a work-around in lieu of full support for Github Enterprise Cloud.