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