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