Margaret Hamilton was the Apollo Director of Software Engineering. In this picture, she is shown inside a mock-up of the Apollo command module.
Hamilton is noted for many accomplishments during the Apollo program. She led the team that wrote all of the software for the guidance computers, invented the term "sofware engineering", and insisted on unit and integration tests of all software. Her work was critical to solving computer problems during Apollo 8 and Apollo 11. In 2016, Hamilton was awarded the Presidential Medal of Freedom (the highest U.S. civilian honor) for her contributions to the Apollo program and software engineering.
She also personally wrote many of the routines for the DSKY display and keypad unit, seen above her head in the picture. It is therefore odd that she had posed with her hand on an unrelated control (apparently a toggle switch or a circuit breaker), instead of the DSKY.
Can anyone identify the control that her hand is on in this picture?