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