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