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