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