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