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