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