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