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