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)(13,14,18,22,19,23,17,20)(15,16,21,25,24,27,28,26)(5,6)(7,11)(8,10)(9,12)(14,20)(15,24)(16,25)(17,18)(22,23)(26,27) involution — undirected(2,4)(5,7,8,12)(6,9,10,11)(13,15,19,24)(14,16,23,27)(17,28,18,21)(20,26,22,25)(7,12)(9,11)(13,16,18,25,19,27,17,26)(14,21,22,24,23,28,20,15)(6,10)(9,11)(13,17,19,18)(14,22,23,20)(15,21,24,28)(16,26,27,25)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.