If you want it in an already existing texture pack, you'll have to unzip that to a location you can remember (in a folder on your desktop, for example). Inside that, find the folder named 'art'. If you open that there should be a file named kz.png.
Either replace that file with the one I linked to above or open the texture pack's file and my file in an image editor, then select, copy and paste the cheatsheet from mine to the texture pack's image, onto a painting you want to replace.
If you just copy my file over the existing kz.png, all other paintings will be the default Minecraft paintings.
Then, select all files and folders in the texture pack's root directory, right-click on any file and select 'Archive', or 'Compress' or something similar. Make sure you compress to a zip file, else it won't work. Give it a name, then copy the new zip file back to the Minecraft texture packs folder and if you've done it correctly, you should now be able to use it in the game.
To just use this paintings file in the otherwise default pack, simply create a folder name 'art' (without quotes), copy the kz.png file into that folder. Select the folder, right-click and select 'Archive' or 'Compress', again making sure you compress to a zip file. Give it a name, copy it to the texture packs folder and it should now appear in the game.