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