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