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