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