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