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