A WebJob is stored under the following directory in your site:
site\wwwroot\App_Data\jobs\{job type}\{job name}
Where {job type} can be either continuous for a job that is always running or triggered for a job that starts from an external trigger (on demand / scheduler).
References:
http://blog.amitapple.com/post/74215124623/deploy-azure-webjobs/#.VDZam_mSx8E