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