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