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