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