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