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)(16,18)(17,21)(19,26)(20,24)(23,28)(25,27) involution — undirected(1,2)(3,4)(5,7,9,8)(6,10,12,11)(14,16)(15,23)(21,26)(24,27)(2,4)(13,15,18,23)(14,20,16,25)(17,24,19,27)(21,28,26,22)(1,2)(3,4)(5,7,9,8)(6,11,12,10)(13,16,18,14)(15,20,23,25)(17,21,19,26)(22,27,28,24)(2,4)(5,8,9,7)(6,10,12,11)(13,17,18,19)(14,21,16,26)(15,24,23,27)(20,28,25,22)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.