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