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