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