As a male, I certainly do not feel that women assume a "cloak of invisibility over the age I fifty. Indeed, in the workplace, mature women often display a confidence level far above many others gained from experience born out of years spent in and out of that workplace.
In the above, women will very often take time out from their careers for childbirth and care. However, on return to the same workplace they find that "things have moved on" in their absence. In that, many find a determination to re-establish themselves and through that set themselves up to gain great confidence and then rapidly become managerial material as they move into their mature years.
I could sight several instances of the above in our workplace and where women with the above career history are now in senior management positions on the operational side of the business.
Of course, it is sometimes the case that women do struggle to re-establish themselves or returning to work following time out for childbirth and associated care, and in that often leave that workplace and settle for lesser positions in a different organisation. However, that should not happen and with the appropriate re-training, should not happen.
However, perhaps that should be the subject of an alternative thread. But, women over the age I fifty being invisible, never, not if they do not wish it to happen, especially in the world of work.