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