Hello Shawtay!
The colors from the Cyclopedia Map are linked to the Measuring Quest, where your job is discover all the map of Tibia.
About the colors they means:
Grey color: This one is liked all those Sub-areas that your character don't have access to, it includes part of the maps where missions are needed to enter, for example: (Furious Crater) or it requires Mini-world changes active to start discovering it, for example: ( Cake Keep Isle, Chyllfroest, Hive Secondary Structure) also is linked to all the places that you cannot access for different reasons: for example: Dawnport, Rookgaard (if you are already on the Mainland) or Isle of Destiny (since it's no longer available).
White Color: It's linked for all the areas and sub-areas that you haven't starting discovered yet, and you can easy start just selecting it by clicking above the name, as the pic below shows:
Pink Color: This color is displayed when an area begins to be discovered but is not 100% complete, and clicking on it will show the% of how much you have done so far.
Green Color: This color means the areas and subareas that you have 100% completed.