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