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