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