One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(6,9)(7,11)(13,14)(15,18)(16,20)(17,19)(21,25)(22,26)(23,27)(24,28) involution — undirected(5,6,8,9)(7,10,11,12)(13,15)(14,18)(16,21)(17,23)(19,27)(20,25)(22,24)(26,28)(2,4)(15,21)(16,24)(18,25)(20,28)(22,23)(26,27) involution — undirected(5,7,8,11)(6,10,9,12)(6,9)(10,12)(14,19)(15,22)(16,24)(18,25)(21,23)(26,27) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.