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