I expect the car will stay clean, so go for a light colour. Look at any small car for ideas. That is effectively what the above car has, it looks great.
Mine is dark blue, with cream seats, blue piping and dark blue carpets. I really like it. Net time it will get cream carpets with darker mats like the one above.
I had a company car, nice new Alfa, that had cream seats and carpets, this made it look much larger that it really was. It stayed clean until I lent it to my sister and two young children for a day. Chocolate and jam sandwiches!! Ordered a new car afterwards!!