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