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