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