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