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)(15,19)(16,20)(21,23)(24,26)(27,28) involution — undirected(1,2)(3,4)(6,9)(10,12)(13,14)(15,21)(16,24)(17,18)(22,27)(25,28) involution — undirected(5,7,8,11)(6,10,9,12)(13,15)(14,19)(16,25)(17,21)(18,23)(20,28)(22,24)(26,27)(2,4)(13,16)(14,20)(15,22)(17,24)(18,26)(19,27)(21,25)(23,28) involution — undirected(6,9)(10,12)(13,14,17,18)(15,23,21,19)(16,20,24,26)(22,28,25,27)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.