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