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