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