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