One vertex per element, one color per generator, with an edge from x to x·s.
(6,9)(10,12)(13,14)(15,19)(16,20)(17,18)(21,27)(22,24)(23,25)(26,28) involution — undirected(1,2)(3,4)(5,6,8,9)(7,10,11,12)(14,18)(16,23)(19,24)(21,28)(2,4)(5,7,8,11)(6,10,9,12)(13,15,17,22)(14,19,18,24)(16,21,23,28)(20,26,25,27)(6,9)(10,12)(13,16)(14,20)(15,21)(17,23)(18,25)(19,26)(22,28)(24,27) 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.