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