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