the femine of "jefe"
Here is a link to a previous question. Maybe it will help.
Hi and welcome to the forum. The dictionary has jefa (m,f ) I always assumed that this meant "la jefa", but now I'm not sure. See this link.
Just use patrón instead. Your boss will like being called "master" and behind his/her back you can refer to them as the "slave-driver". Of course, that also defines your status.