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