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