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