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