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