<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Models\DirectorySetting;
use Microsoft\Graph\Beta\Generated\Models\SettingValue;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new DirectorySetting();
$requestBody->setTemplateId('08d542b9-071f-4e16-94b0-74abb372e3d9');
$valuesSettingValue1 = new SettingValue();
$valuesSettingValue1->setName('AllowToAddGuests');
$valuesSettingValue1->setValue('false');
$valuesArray []= $valuesSettingValue1;
$requestBody->setValues($valuesArray);
$result = $graphServiceClient->groups()->byGroupId('group-id')->settings()->post($requestBody)->wait();