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