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