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