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