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