Explanation is beneath the tweet, the furthest point is the top 5% in Europes top 5 leagues.
So Sterling ranks among the top 5% in Europe for touches in the box, expected assists per 90 minutes, and xG chain, which measures how involved players are in phases of play which lead to a chance which has a high probability of being a goal.
Conversely he's very low in regards to through balls etc.
The diagram is a way of having a visual way of comparing a players stats to the best in Europe. The bigger the star, the better the player.
Ted Knutson, the guy that produces them, works for a company which consults with PL teams to bring analytics to a practical level.