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