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