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)(11,20,23,16)(12,24)(13,15)(14,19)(17,25)(18,27)(21,34,36,38)(22,31,37,28)(26,29)(30,35,33,40)(32,39)(1,3)(2,5)(4,8)(6,7)(10,15,19,18)(16,28,20,31)(17,29,32,24)(30,34,33,38)(3,8)(5,7)(9,11)(10,16)(12,21)(13,22)(14,23)(15,28)(17,30)(18,31)(19,20)(24,38)(25,35)(26,36)(27,37)(29,34)(32,33)(39,40) involution — undirected(2,6)(5,7)(9,12,13,25,14,26,27,39)(10,17,18,24,19,32,15,29)(11,21,22,35,23,36,37,40)(16,30,31,38,20,33,28,34)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.