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