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