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