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