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