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