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