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