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