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)(11,15)(12,14)(13,16)(17,19)(18,23)(20,21)(22,24)(25,26,31,28)(27,29,34,32)(30,33,38,36)(35,37,40,39)(1,2)(3,6)(4,7)(5,8)(9,10,14,12)(11,17,19,15)(13,16,21,20)(18,24,22,23)(25,27)(26,32)(28,29)(30,35)(31,34)(33,39)(36,37)(38,40)(10,12)(13,21)(15,17)(18,22)(27,34)(29,32)(35,40)(37,39) involution — undirected(1,3,5,4)(2,6,8,7)(9,11,14,19)(10,15,12,17)(13,22,21,18)(16,24,20,23)(25,28,31,26)(27,32,34,29)(30,33,38,36)(35,37,40,39)(1,4,5,3)(2,7,8,6)(9,12,14,10)(11,17,19,15)(13,20,21,16)(18,24,22,23)(25,29,31,32)(26,27,28,34)(30,37,38,39)(33,35,36,40)(9,13)(10,16)(11,18)(12,20)(14,21)(15,23)(17,24)(19,22)(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.