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