Whatever you do, don’t dye your hair, nothing looks more obvious
TBF, my wife has her hair dyed (she really can’t accept the fact she is going grey and it really does upset her) but you really can’t tell. But she does have it done professionally (she has to as she started to get allergic reactions to the DIY stuff) at great expense. Still, it makes her feel more comfortable with her appearance so that’s fine by me.
Personally I used to dye my hair all sorts of colours (either at the hairdressers or at home) but stopped as soon as the grey started to appear as I didn’t want it to look like I was hiding something.