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