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