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