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