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