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