Try pairing a grey plaid blazer with grey dress pants if you're going for a neat, dapper outfit. A pair of black leather tassel loafers will tie this whole look together. Ideal to convey that you're mature and confident enough to hold your own in the sartorial department.
Grey Plaid Blazer with Grey Dress Pants Dressy Warm Weather Outfits For Men After 40
Wear a grey plaid blazer and grey dress pants for a proper sophisticated getup. This outfit is probably exactly what you're looking for as a mature guy.