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