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