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