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