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