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