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