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