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