Enabling xautoload module throws an error originating from the sendgrid_integration_xautoload

It throws the following stack trace:

Exception: Composer directory 'sites/all/modules/contrib/sendgrid_integration/vendor/composer' does not exist. sites/all/modules/contrib/xautoload/src/Discovery/ComposerDir.php:23 [error]
Stack trace:
#0 /sites/all/modules/contrib/xautoload/src/Adapter/ClassFinderAdapter.php(120): Drupal\xautoload\Discovery\ComposerDir::create('sites/all/modul...')
#1 /sites/all/modules/contrib/sendgrid_integration/sendgrid_integration.module(17): Drupal\xautoload\Adapter\ClassFinderAdapter->composerDir('sites/all/modul...')
#2 /sites/all/modules/contrib/xautoload/src/Phases/HookXautoload.php(107): sendgrid_integration_xautoload(Object(xautoload_InjectedAPI_hookXautoload), '/Users/pub/www/...')
#3 /sites/all/modules/contrib/xautoload/src/Phases/HookXautoload.php(69): Drupal\xautoload\Phases\HookXautoload->runHookXautoload(Array)
#4 /sites/all/modules/contrib/xautoload/src/Phases/DrupalPhaseControl.php(118): Drupal\xautoload\Phases\HookXautoload->enterMainPhase()
#5 /sites/all/modules/contrib/xautoload/src/Phases/DrupalPhaseControl.php(146): Drupal\xautoload\Phases\DrupalPhaseControl->enterMainPhase()
#6 /sites/all/modules/contrib/xautoload/xautoload.module(88): Drupal\xautoload\Phases\DrupalPhaseControl->checkNewExtensions()

The cause of the error originates from the following hook:

sendgrid_integration_xautoload

where it attempts to load the composer directory for the module, but if you haven't loaded the module with composer then it throws this exception.