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