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