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