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