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