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