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