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