There's certainly no shortage of graphical mods for Fallout 4, but with the use of SweetFX Shader Suite and some fine tuning you can alter the appearance of post-nuclear wasteland to look more like a world from a Telltale game.
Following the directions from Reddit users "Reddit_is_wrong" (clever), you can get your game to look like this:
It's worth noting that to achieve the desired effect you need to use three other mods alongside the tweak, although results still may vary.