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