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