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