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