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