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