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