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