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