Artificial selection is more akin to how we ended up with the tea cup Chihuahua and the Puffin Hound. Both are massively different from the very original domesticated dogs, changed by intentional genetic forces placed upon them (i.e. forced breeding).
Natural selection that we can see here and today would be mice starting to speciate as the pale-coated deer mouse splits from the common deer mouse because of the light-colored sandy environment it lives in. Humans, or other intelligent beings, had nothing to do with the environmental changes in the past five thousand years that lead to the sandy light-colored soil appearing in the middle of Nebraska. So it's natural selection that the mice are changing the color of their coats over time to better adapt to the light-colored ground, compared to their cousins that live on darker soil.
To contrast this better, there's the example of the peppered moths in the United Kingdom. They were originally a light color, allowing them to blend in with the light-colored bark of trees that blanketed the countryside. As the Industrial Revolution got underway, soot from the factories around the countries rained down, sticking to the bark of the trees and blanketing them in a dark patchwork. The light-colored moths stood out against the dirty bark and were picked off easily by their natural predators, encouraging any of them with mutations that caused their wings to be peppered with dark spots to thrive. Which gave rise to the peppered moth as it's known today.
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8225000/8225219.stm