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