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