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