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