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