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