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