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