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