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