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