1. Your VS Source Control Explorer would normally look like below and will not show the deleted files.
2. Go to Tools --> Options in Visual Studio menu and open the options. Select Source Control --> Visual Studio Team Foundation Server and tick the option "Show deleted items in Source Control Explorer" and click OK.
3. Now you can see the deleted files appear in Source Control Explorer. Right click on the Folder/File you want to restore and click "Undelete" to get it restored.