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