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