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