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