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