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