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