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