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