this review I found quite in line with my impressions in general.
http://arstechnica.com/gaming/2016/10/mafia-3-review/
but also specifically for graphics: "Playing on my fairly powerful i5 4670K with 8GB RAM and a hefty GTX 1070, Mafia 3 looks like complete bum in places. The night time sections look great, with some lovely ambient lighting, but by day the entire game is coated in a muddy haze that looks like a bad Instagram filter. The sky boxes look like something from a PlayStation 1, the draw distance is shoddy, and the pop-in sometimes throws oncoming traffic into your face about three metres in front of you.

Worst of all, the game seems to be rendered at a far lower resolution than I was setting it to, looking like a 720p game blown up to 1440p. It's a bizarre mix of occasionally good looks contrasted with some supremely bad ones, and it tops off an already lacklustre game."