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