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