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