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