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