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