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