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