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