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