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