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