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