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