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