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