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