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