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