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