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