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