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