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