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