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