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