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