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