It is, in fact, the largest symmetrical Venn diagram ever created. As New Scientist sagely points out, it's possible to create massive non-symmetric Venn diagrams that require circles to be stretched, squeezed and turned in on themselves, but "such geometrical gymnastics were distasteful to British logician John Venn, who created the diagrams in 1880."
Instead, mathematicians try and develop the biggest symmetrical diagrams they can. Sadly, they are proven to exist only for Venn diagrams with a prime number of sets — and the previous record was just seven.
This bad boy, however, boasts an impressive 11-set capability. You can read more about how it came into being on New Scientist or, if you're keen, read the rather more tecnical explanation hosted over at arXiv. [arXiv via New Scientist]