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