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