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