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