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