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