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