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