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