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)(15,20,24,27,26,28,25,23)(1,2)(3,4)(5,7)(6,10)(8,11)(9,12)(13,15,18,26)(14,20,22,28)(16,27,21,23)(17,25,19,24)(2,4)(13,16,18,21)(14,17,22,19)(15,23,26,27)(20,24,28,25)(6,11)(7,12)(13,14)(15,20)(16,17)(18,22)(19,21)(23,24)(25,27)(26,28) involution — undirected(5,8,9,10)(6,7,11,12)(13,17,18,19)(14,16,22,21)(15,24,26,25)(20,23,28,27)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.