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)(25,26,32,35)(27,36,31,33)(28,30,29,34)(37,39,38,40)(1,2)(3,6)(4,7)(5,8)(9,11,14,17)(10,13,15,23)(12,18,21,24)(16,22,19,20)(25,27,32,31)(26,33,35,36)(28,38,29,37)(30,39,34,40)(1,3)(2,5)(4,8)(6,7)(10,15)(11,17)(16,19)(18,24)(25,28,32,29)(26,34,35,30)(27,37,31,38)(33,39,36,40)(3,8)(5,6)(9,11)(10,13)(12,18)(14,17)(15,23)(16,22)(19,20)(21,24)(25,29,32,28)(26,30,35,34)(27,38,31,37)(33,40,36,39)(1,2)(3,5)(4,7)(6,8)(9,12,14,21)(10,16,15,19)(11,18,17,24)(13,22,23,20)(25,30)(26,28)(27,39)(29,35)(31,40)(32,34)(33,38)(36,37)(1,3)(2,6)(4,8)(5,7)(9,13)(10,17)(11,15)(12,20)(14,23)(16,18)(19,24)(21,22)(25,31,32,27)(26,33,35,36)(28,38,29,37)(30,40,34,39)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.