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