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