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