In that particular example, wouldn't it be more anonymous to just have 6 outputs of 61.04976087 BTC? (That's the total amount less tx fees divided by 6, or 3 yellows and 3 change outputs of all exactly the same amount).
That way, even the "change" outputs can no longer be tied to the three people.
The three people contributed different amounts to the transaction, so they get different amounts of change.
The person paying for the transaction (the 'taker' in JoinMarket terminology) decides the amount of the yellow outputs, and the other two people (the 'makers') go along with that. It's only the yellow amount which is to be considered 'joined'.
Note that we could figure out which of the three people was the taker by summing the inputs and outputs of each colour. We'll find that two of the thee made a small profit on this transaction (the makers) and one took a loss (the taker).
If the maker had wanted to mix his whole wallet in this transaction he could done so. He must have only needed 70 BTC mixed at this time, for whatever reason.
Also, try following the yellow outputs - you'll see that all three of them went on to further coinjoin transactions for different amounts.