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