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