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)(11,15)(12,19)(13,14)(16,21)(17,22)(18,24)(20,23)(25,26,31,33)(27,37,38,32)(28,29,35,34)(30,40,39,36)(1,3,5,8)(2,6,7,4)(10,14)(11,17)(16,19)(18,20)(25,27)(26,32)(28,39)(29,40)(30,35)(31,38)(33,37)(34,36)(2,7)(3,8)(10,14)(11,17)(16,19)(18,20)(26,33)(27,38)(28,35)(36,40) involution — undirected(1,3)(2,4)(5,8)(6,7)(9,10)(11,15)(12,16)(13,14)(17,22)(18,23)(19,21)(20,24)(25,28,31,35)(26,34,33,29)(27,39,38,30)(32,36,37,40)(1,3)(2,6)(4,7)(5,8)(9,11,13,17)(10,15,14,22)(12,20,21,18)(16,24,19,23)(25,29,31,34)(26,35,33,28)(27,36,38,40)(30,32,39,37)(1,4,5,6)(2,8,7,3)(9,12,13,21)(10,16,14,19)(11,18,17,20)(15,23,22,24)(25,30,31,39)(26,36,33,40)(27,35,38,28)(29,32,34,37)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.