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