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