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