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