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