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