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