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