It seems that the DIY Graphene actually uses a Beyerdynamic DP100 shell, not mx760 like the description says. When searching google for Sennheiser mx760's you will see that the mx760 shells actually look like
these. When comparing google image results, the front cover for both the DP100 and mx760 looks identical in design. The rear shell port design is completely different though. I have a feeling that mx760 driver units might just snap on to the DP100 rear shell as if they were made for each other. If that is true, it might explain the mx760 term being used in listings for DP100 shells.
I couldn't find DP100 shells on Aliexpress, but did find a
cheap assembled DP100. I found listings for DP100 shells on TaoBao
here and
here. I also found
this other site selling them. It seems to be the same listing photos as the TaoBao link, but the site offers worldwide shipping at checkout. So does TaoBao, but TaoBao can be complicated if you have never used it before. This site might be easier, but I make no guarantees since I have never even heard of it until today.