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