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