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