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)(15,23)(16,18)(17,21)(19,22)(20,25)(24,28)(26,27) involution — undirected(1,2)(3,4)(6,10)(11,12)(13,14)(15,23)(16,18)(17,21)(19,22)(20,25)(24,28)(26,27) involution — undirected(5,7,9,8)(6,11,10,12)(13,15,18,25,19,26,17,24)(14,20,21,23,22,28,16,27)(2,4)(5,8,9,7)(6,12,10,11)(13,16,17,22,19,21,18,14)(15,23,24,20,26,27,25,28)(6,10)(11,12)(13,17,19,18)(14,21,22,16)(15,24,26,25)(20,23,28,27)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.