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