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