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