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