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