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