This is a very good visual representation. Whether it is the best, or not, depends on the purposes:
First, you can see right away where the top 25% (4th quartile) scored by looking at the right hand whisker.
Second, you get two measures of variation for the data, the range and the interquartile range. Finally, by looking at the left whisker, you can see that most of the variation comes from the bottom quartile: 3/4 of the students scored between 80 and 100, while 1/4 scored between 80 and 50.
As a teacher, I would want more detail about the bottom quartile. It might be that one student scored 50 and everyone else scored between 70 and 80. But I wouldn't need to have it graphically represented. This graph shows me that the class overall is in good shape: The median is close to 90. But there is at least one student, and up to 25 % of the class who did poorly on an exam that otherwise looks very easy.
