Sketch is a self contained app unique to the MacOS that can be utilized on MacinCloud servers.
How to install Sketch without admin access
Because Sketch is a self-contained app, to install, all you need to do is download the software from Sketch's official website onto your MacinCloud server. After this is done, simply drag and drop the software onto the desktop of your MacinCloud server and run the software. This will allow you to utilize Sketch on your server without requiring admin access or assistance to install it.