Sous Vide Beef steaks look overcooked at 59°C and 56.5°C
If your sous vide machine is cooking to the right temperature then your steak is not overdone. That's the beauty of the process, your meat will go up to the temperature you set and no higher. You need to take the temperature of the center of the meat when you take it out. If the temperature of the meat is higher than you set the machine to then something is wrong with your machine. If the temperature is right then that is how the meat looks when cooked, unless you have marinated it or it's getting coloring from something in the bag. Maybe it's old, or hasn't been aged at all. 

Different cuts of beef have different textures and colors before and after cooking, and depending on whether the meat has been aged or not, how it was aged if it was, and if it's close to spoilage. It's very hard to say in this case, what you need is data.