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