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