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