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