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