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