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