The RGB Hex colour chart is a very large (183kB) PNG file, and is sized to fit on a standard A4 piece of paper. It shows the 216 so-called "web safe" or "non-dithering" colours (there are actually only 22 web safe colours, but those are revolting).
If you link to this resource, please link to this page and not to the image directly.
And finally, if you like the cheat sheets, and want to say thanks, please consider buying me something from my Amazon Wishlist. Thankyou very much to those who have already hunted it down and sent me something nice - I'm very grateful!