Consider teaming an orange long sleeve shirt with black chinos if you want to look casual and cool without much work. Want to tone it down with shoes? Choose a pair of sandals for the day. This pairing is a shining example 40-year-old gentlemen can very well slay in the style department.
If you don't take fashion too seriously, go for casually dapper style in a white long sleeve shirt and black chinos. To introduce a more relaxed finish to this getup, introduce sandals to the mix. This getup is a clear example gentlemen in their 40s can very well slay in the style department.