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