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