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