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