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