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