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