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