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