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