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