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