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