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