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