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