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