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