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