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)(13,14)(15,19)(16,26)(17,22)(18,23)(20,25)(21,27)(24,28) involution — undirected(6,9)(7,11)(13,15)(14,19)(16,24)(17,25)(18,27)(20,22)(21,23)(26,28) involution — undirected(2,4)(13,15,24,27,17,25,18,16)(14,20,28,26,22,19,23,21)(6,9)(10,12) involution — undirected(5,7,8,11)(6,10,9,12)(13,16,24,15,17,27,18,25)(14,21,28,20,22,26,23,19)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.