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