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