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)(15,19)(16,21)(17,20)(18,22)(23,26)(24,27)(25,28) involution — undirected(1,2,4,3)(5,7)(6,9)(8,11)(10,12)(13,15,17,23)(14,19,20,26)(16,25,24,18)(21,28,27,22)(6,10)(7,11)(14,20)(15,23)(16,24)(22,28) involution — undirected(6,10)(9,12)(13,16,18,15,17,24,25,23)(14,21,22,19,20,27,28,26)(1,3,4,2)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.