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