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