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