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)(13,14,18,15,17,20,26,22)(16,19,25,21,24,23,27,28)(5,7)(6,9)(8,12)(10,11)(13,14,18,15,17,20,26,22)(16,23,25,28,24,19,27,21)(2,4)(13,15,18,20,17,22,26,14)(16,21,25,23,24,28,27,19)(7,12)(9,11)(13,16)(14,19)(15,21)(17,24)(18,25)(20,23)(22,28)(26,27) involution — undirected(6,10)(9,11)(16,24)(19,23)(21,28)(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.