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