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