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