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