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