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