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