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