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)(25,26,30,31)(27,34,29,32)(28,36,38,33)(35,39,37,40)(1,2)(3,6)(4,5)(7,8)(11,12)(15,18)(19,20)(22,23)(26,31)(32,34)(33,36)(39,40) involution — undirected(2,5)(6,8)(9,11,14,12)(10,15,17,18)(13,19,21,20)(16,22,24,23)(25,27,30,29)(26,32,31,34)(28,37,38,35)(33,40,36,39)(3,7)(6,8)(9,12,14,11)(10,15,17,18)(13,19,21,20)(16,23,24,22)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,38)(37,40)(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)(27,35,29,37)(32,39,34,40)(1,3)(2,6)(4,7)(5,8)(9,13)(10,16)(11,19)(12,20)(14,21)(15,22)(17,24)(18,23)(25,29,30,27)(26,32,31,34)(28,37,38,35)(33,39,36,40)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.