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