Yes, different organs may have different colors and each organ may it's self have different colors depending on "IF" it is Healthy or Sick!
This subject is not understood by anyone that I have ever met or known about, and I do not know of any website which may provide any direct info about it!
You may learn some about different colors relating to different Minerals by studying some fields of Geology?
Also some great Painters of the past who knew about mixing different minerals to produce different colors probably knew more about this than anyone else did!
Yet, this subject may not be understood fully, for this is not different than most everything else!
As not everything may be as it may first seem to be!
In other words what would generally be considered, for example, If you see a certain color in an organ, is this color representative of the Mineral which is being utilized by the organ "OR" is this the Mineral which the organ is not being utilized by the organ, thus giving it the color you "THINK" you see?
Every color of the Electro-magnetic light spectrum may represents a different Frequency and then there are the frequencies which are not visible to the human eye which carry each different Frequencies!
The colors of the organs may be all represented in nature!
The greater and more intense the color the foods may be, may reflect a Greater amount of Minerals in the foods of more varied amounts!
This is why it may be best to eat foods in season and thus provide the body with a much Greater variety of minerals thru-out the year, vs eating a meat and potatoe or coke and hambuger Diet!