<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Models\Group;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new Group();
$requestBody->setDescription('Self help community for library');
$requestBody->setDisplayName('Library Assist');
$requestBody->setGroupTypes(['Unified', ]);
$requestBody->setMailEnabled(true);
$requestBody->setMailNickname('library');
$requestBody->setSecurityEnabled(false);
$result = $graphServiceClient->groups()->post($requestBody)->wait();