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