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