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