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