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