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