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