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