Apple: Microsoft Outlook Temp Folder for Mac OS X

You should be able to access the Outlook Temp folder by following the steps below:

1. At the menu bar, click on Go
2. Press the alt / option key and the Library should appear
3. Click on Library
4. Find and click on the Caches folder
5. Find and click on the TemporaryItems folder 

Now, you should see the Outlook Temp folder in the TemporaryItems folder.