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