MTF charts only measure sharpness/detail and contrast of a lens.If these are optimum then it would translate into
"nice colour" bearing in mind the type of camera sensor and the photo processing algorithm/software that is used.
Norman Koran has a comprehensive database,if you can understand all of the info and the effort you put in then you will be a knowledgeable photographer. Also note that MTF charts like statistics can be manupulated to
serve an agenda like marketing.Who would want to show bad results so you must know how to interpret such data.
There are no fixed standard for MTF charts like resolution test charts and variables used to compile MTF data.
Different lenses can affect the color of an image, yes. If you shoot the same scene with a sigma, a tamron and your normal lens, same focal length, aperture, etc, you'll almost certainly see some differences in terms of color and contrast.