I am gifted at reading gibberish, so you're in luck.
Here is your answer:
Red = shares sold at the bid (which they call "sells") Green = shared bought at the ask (which they call "buys") Grey = shares bought or sold between the ask and bid (which can't be classified as "buys" or "sells")
Same as on the website.
Keep in mind that this is a little misleading, because every transaction is both a buy and a sell.