Currently there seems to be no offline installer for the newly released Visual Studio 2017 but creating one is as easy as downloading all features and then packaging them into a .iso file yourself.
https://blogs.msdn.microsoft.com/mapo/2017/03/13/visual-studio-2017-offline-installer/
https://blogs.msdn.microsoft.com/mapo/2017/03/13/visual-studio-2017-offline-installer/