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