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