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)(11,16)(12,17)(13,18)(14,15)(19,21)(20,23)(22,24)(25,26,31,34)(27,32,30,40)(28,33,38,29)(35,36,37,39)(1,3,5,8)(2,6,7,4)(10,15)(11,18)(17,23)(19,24)(25,27,31,30)(26,32,34,40)(28,35,38,37)(29,39,33,36)(2,7)(3,8)(12,20)(17,23)(19,24)(21,22)(25,28,31,38)(26,29,34,33)(27,35,30,37)(32,39,40,36)(1,3)(2,4)(5,8)(6,7)(9,11,14,18)(10,16,15,13)(12,19,20,24)(17,21,23,22)(25,28)(26,33)(27,35)(29,34)(30,37)(31,38)(32,36)(39,40)(1,3)(2,6)(4,7)(5,8)(9,12)(10,17)(11,19)(13,22)(14,20)(15,23)(16,21)(18,24)(25,29,31,33)(26,28,34,38)(27,36,30,39)(32,37,40,35)(1,4,5,6)(2,8,7,3)(9,13,14,16)(10,18,15,11)(12,21,20,22)(17,19,23,24)(25,30,31,27)(26,32,34,40)(28,37,38,35)(29,39,33,36)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.