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