Why not go for a white and black print crew-neck t-shirt and blue ripped jeans? As well as very functional, these items look awesome teamed together. Black and white athletic shoes will tie your full ensemble together. When it comes to casual clothing for middle-aged gentlemen, this getup is ideal.
If the situation allows casual style, you can dress in a white and black print crew-neck t-shirt and black chinos. If you need to easily play down this getup with shoes, why not introduce a pair of black and white athletic shoes to the equation? And if we're talking casual style for 40-year-old gentlemen, this getup is ideal.