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