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