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