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