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