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