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