What I find interesting is what we define as "invisible". Also, are we talking about professionally or personally? Ageism is a real problem professionally and I see it all the time in the tech world. That being said I know a lot of older people who work all the time and the one thing they have in common is they don't act old.
Personally, I have never felt less "invisible" in the last few years. I have decided to live life to its fullest and revel in not being invisible. To that end I make the same sort of effort I made in my 20s. I present myself how I feel; smart, sexy and put together.
However, I have friends who groan that their lives lack sexual partners and that they are feeling like life is over for them. Sadly most of these friends stopped taking care of themselves and look so dowdy compared to how they presented themselves 10 years ago. Frankly I wouldn't want to have sex with them if they were the last living things on life and strapped on a really nice sized device.