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