I would doubt Ubisoft, who have no doubt been developing a game like Watch_Dogs for several years, will have taken the time to make a unique version just for the PS4.
The game is on 360, PS3 and Wii U, three consoles which are all on the same basic level when it comes to graphics, right? They'll all be running the same version of the game, right? For the PS4 version to be any different, Ubisoft will have had to put in months of extra work and re-tool the game's engine to work with the PS4's architecture, right? Meaning they'd basically need to have a totally different version of the game just for the PS4, right? Which would be a silly thing to waste time on considering the vast majority of their sales will be on 360 and PS3, right? tIt'd be easier to just port the existing version onto PS4, right?
I would wager money that the PS4 version will not be noticably different to any other version. It might load faster, who knows. But look different? Let's all just be serious again, for a change.