@Sergey Stepanov - Welcome to Microsoft Q&A and thanks for reaching out to us.
Microsoft Graph PowerShell supports functionalities and features from MSOnline and Azure AD PowerShell. Microsoft Graph PowerShell or API does not have a direct mapping for that command. See if you can use this command:
Get-MgGroupMemberOfAsGroup -GroupId $groupId
It will list the group membership for a given group.
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