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