I think it can relate to modern day society in many ways. People still love to party, among so many of the other themes in the Great Gatsby.
The love that Gatsby and Daisy had I believe can still be found today, adultery is still common in our modern day society, as well materialism.
These are just a few examples.
I hope I helped! If you need any more help or would like further explanation just let me know! :)