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