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