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