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