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