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