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