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