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