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