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