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