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