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