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