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