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