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