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