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)(11,19)(12,14)(13,16)(15,17)(18,23)(20,21)(22,24)(25,26,31,34)(27,30,33,39)(28,29,32,38)(35,36,37,40)(2,3)(6,7)(9,11,15,13)(10,16,17,19)(12,22,23,20)(14,21,18,24)(25,27)(26,30)(28,35)(29,36)(31,33)(32,37)(34,39)(38,40)(1,3,5,2)(4,7,8,6)(10,17)(14,18)(16,19)(21,24)(27,33)(30,39)(35,37)(36,40)(1,4,5,8)(2,6,3,7)(9,12)(10,18)(11,20)(13,22)(14,17)(15,23)(16,21)(19,24)(25,28)(26,29)(27,35)(30,36)(31,32)(33,37)(34,38)(39,40)(9,13,15,11)(10,19,17,16)(12,20,23,22)(14,24,18,21)(25,29)(26,32)(27,36)(28,34)(30,37)(31,38)(33,40)(35,39)(9,14,15,18)(10,12,17,23)(11,21,13,24)(16,22,19,20)(25,30,31,39)(26,33,34,27)(28,36,32,40)(29,37,38,35)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.