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