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