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