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