select permission was denied on the object 'sysjobs'
You use the "SQL Server Agent Fixed Database Roles" in msdb (MSDN link).

And a "how to" for SSMS: "How to: Configure a User to Create and Manage SQL Server Agent Jobs (SQL Server Management Studio)"

Note: you need a user (MSDN) in one of these roles: no need to GRANT rights to sqlagentoperator