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