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