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