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