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