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