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