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