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