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