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