Usually, a mentor has to come from your professional network. Maintaining your professional network requires work. In your case, your past mentors are a place

Usually, a mentor has to come from your professional network. Maintaining your professional network requires work. In your case, your past mentors are a place to start that work. It is important to demonstrate a maturity and attitude that makes it make sense for a mentor to invest the time in the mentoring relationship. Good luck.