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