You can use those color codes, an RGB tuple, or you can also use hex colors, which are very easy and customizable (HTML hex color charts are widely available on the web).
Here's the documentation on the color codes: http://matplotlib.org/api/colors_api.html
What 'bo' and 'ro' actually are are two concatenated strings: a one-character string representing the color plus a one-character string representing the line style, in this case, a dot. See http://matplotlib.org/users/pyplot_tutorial.html, where it explains that if you use 'b-' instead of 'bo', it means a blue line instead of a blue dot.
This means that you can use any of the color codes in the colors api link above, followed by an o. For example, a green dot should be 'go'.
If the one-character strings for colors don't suit your needs, you can follow another format:
plot(x, y, color='green', linestyle='dashed', marker='o').
You can insert color names, hex codes, or RGB tuples in the color field.