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