One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,19)(12,16)(13,18)(14,17)(15,21)(20,24)(22,23)(25,26,31,35,30,34,40,29)(27,33,37,38,28,32,39,36)(1,3)(2,5)(4,7)(6,8)(9,11,14,21)(10,15,17,19)(12,22,13,20)(16,24,18,23)(25,27,30,28)(26,32,34,33)(29,38,35,36)(31,37,40,39)(2,6)(3,7)(9,12,14,13)(10,16,17,18)(11,20,21,22)(15,23,19,24)(25,28,30,27)(26,33,34,32)(29,36,35,38)(31,39,40,37)(2,6)(5,8)(10,17)(11,21)(16,18)(20,22)(27,28)(32,33)(36,38)(37,39) involution — undirected(9,13,14,12)(10,18,17,16)(11,20,21,22)(15,23,19,24)(25,29,40,34,30,35,31,26)(27,36,39,32,28,38,37,33)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.