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