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