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