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)(21,23,24,22)(25,26)(27,36)(28,34)(29,30)(31,33)(32,35)(37,38)(39,40)(1,2)(3,7)(4,5)(6,8)(10,15)(11,20)(12,18)(22,23)(25,27,32,31)(26,33,35,36)(28,37,30,40)(29,38,34,39)(2,5)(6,7)(10,15)(13,17)(16,19)(22,23)(25,28,32,30)(26,34,35,29)(27,37,31,40)(33,39,36,38)(9,11)(10,16)(12,21)(13,22)(14,20)(15,19)(17,23)(18,24)(25,29)(26,28)(27,38)(30,35)(31,39)(32,34)(33,37)(36,40) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,12,14,18)(10,17,15,13)(11,21,20,24)(16,23,19,22)(25,30,32,28)(26,29,35,34)(27,37,31,40)(33,39,36,38)(1,2)(3,6)(4,5)(7,8)(9,13,14,17)(10,18,15,12)(11,22,20,23)(16,24,19,21)(25,31,32,27)(26,33,35,36)(28,37,30,40)(29,39,34,38)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.