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