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