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