<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Models\SharePointGroup;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new SharePointGroup();
$requestBody->setOdataType('#microsoft.graph.sharePointGroup');
$requestBody->setTitle('Sample Group');
$requestBody->setDescription('This is a sample description');
$result = $graphServiceClient->storage()->fileStorage()->containers()->byFileStorageContainerId('fileStorageContainer-id')->sharePointGroups()->post($requestBody)->wait();