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