
Hi @Demo Demo,
Per my research, Graph api doesn't support SharePoint groups yet. Here is a similar issue with yours, please make a reference.
As a workaround, I will recommend you to use rest api to get all groups in the site. We can uese following api
https://{sitecollection}/_api/web/sitegroups
Also I noticed that some end users have also proposed the same request, it is highly recommended that you can vote this ticket. Many features of our current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future. Thanks for your understanding.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.