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