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