Perhaps try to separate the colors into 10 buckets instead of 100, then make a list out of it.

colors = ["#first", "#second", "#third", ..., "#tenth"]

Then, write a simple function to assign the number to the corresponding color.

def pick_color(num):
    if num in range(0, 10):
        return colors[1]
    elif num in range(10, 20):
        return colors[2]

...and so on.

This is one standard representation for a color. Think of the input as being in binary or hexadecimal, rather than decimal. The first 8 bits are the red part, the middle 8 bits are the green part, and the last 8 bits are the blue part.

You'll likely want to use integer division to move the wanted part to the right side of your number, then use the modulus operator, %, to grab the eight bits needed. Another way to attack the same idea is to use the bit-wise and operator, &, to get those last bits.

That should be enough of a hint to get you moving.