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